An Error-Toleranting Operation And Protection System Based On Double PLC For Hoist

This abstract is based on the digital reconstruct of DC hoist auxiliary-mine for XUCHANG COALMINE ZI-BO Coal-Electric Corporation. It aims at the high reliability of hoist system. And it is based on error-toleranting theory and method. It provides a high reliability Double PLC error-toleranting system.It be made up of operation protecting PLC and routing monitor PLC From function of Double PLC. (l)Main functions of PLC's operation protection1) Declutch and band-type brake of controlled hydraulic pressure braking system;2) execute operation program and create driving signal and direction;3) Protection and deadlock of all kinds of faults;Main functions of the route supervision PLC is: Combined some operation singal, protection signal, set route parameters and axis coder signal to have logical operation and processing. And it can also produce set speed signal which is needed by hoist. In order to reduce setup, mechanical impact in braking process, improve hoist' s control precision, speedup and speed-down segmentshould be S type curve of set speed signal. We can adjust slowdown to fixed value by PLC' s actual operation, which can ensure precise of shut down point. Additionally, route monitor PLC can transfer axis coder signal to cage's position and online speed in shaft through software processing. This software processing's route tracing method is flexible, credible and high precise. If we choose axis coder of high resolution, fix position precise can be ensure.Meanwhile route error of slippage and wire rope's elongation can be corrected by shaft' s timing switch.Two sets of PLC are both independent and mutual supervision. It can also protect (pulleying, excessive speed, wire rope' s slippage) and mutual resertation. All of these can improve credibility of route's monitor. (2)Lead diversification into PLC' s software principle, research permitting...